Data centers route massive quantities of data. Currently, data centers may have a throughput of 5-7 terabytes per second, which is expected to drastically increase in the future. Data centers consist of huge numbers of racks of servers, racks of storage devices, and other racks, all of which are interconnected via a massive centralized packet switching resource. In this resource, electrical packet switches are used to route data packets in these data centers. Electrical packet switches switch or route packets based on a packet header with inter-stage buffering, which can overflow, causing packet loss and the need for packet retransmission.
The racks of servers, storage devices, and input-output devices contain top of rack (TOR) packet switches which combine packet streams from their associated servers and/or other peripherals into a lesser number of very high speed streams per TOR switch. The TOR switch outputs a packet stream to the packet switching fabric. Also, the TOR switches receive the returning switched streams from the packet switching core and distribute them to servers within their rack. There may be 4×40 Gb/s streams from each TOR switch to the packet switching core, and the same number of return streams. Additionally, there may be one TOR switch per rack, hundreds to ten thousands of racks, and hence hundreds to ten thousands of TOR switches in a data center.
Photonic packet switches include a family of network communication elements that can be used as the core switch in a data center, or used in any other packet switching environment. In a photonic packet switch, packets are switched by photonic devices, without converting them to electrical signals. Photonic switches tend to have challenges in speed of setting up and taking down connections but exhibit huge bandwidth throughputs when a connection is in place.